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A team of scientists at the National Aeronautics and Space Administration (NASA) found that last year’s forest fires in Canada released roughly 640 million metric tonnes of carbon in the environment. This is equivalent to an industrialised country’s annual carbon emissions.
The study was published on August 28 in the Nature journal, by scientists at NASA’s Jet Propulsion Laboratory in Southern California.
A combination of extreme heat and lack of rainfall in the region led to ‘tinderbox conditions’ across Canada's forests which began in May and lasted till September. While the number of fires was not unusual, many grew to massive sizes, with hundreds of fires covering areas larger than 10,000 hectares.
“The 2023 fire season was the warmest and driest for Canadian forests since at least 1980, resulting in vast carbon emissions from forest fires…comparable in magnitude to India’s annual fossil fuel CO2 emissions”, the study stated.
Canadian forests comprise nearly 8.5 per cent of global forested area, of which 15 million hectares got incinerated in the fires, leading to more than 200,000 evacuations and deterioration in air quality.
The scientists used inverse modelling of satellite observations of carbon monoxide (CO), using the Tropospheric monitoring instrument (TROPOMI) from outer space to measure the CO2 emissions.
Researchers also observed that while the fossil fuel emissions were immense, as the forests recuperated and grew back, it would be absorbed by the Earth’s ecosystem. Using data from 27 climate models, they also projected temperature and rainfall patterns for the coming decades under a moderate warming scenario.
The results show significant temperature increases on the horizon with average temperatures during the 2050s mimicking those during Canada's forest fires.
While rainfall is also projected to increase, it won't be enough to offset the higher temperatures. This combination is likely to lead to drier conditions in Canadian forests as the century progresses.
The massive wildfires have also raised concerns about the future of this carbon sink. The Canadian forests have been a significant carbon sink, absorbing about 366 million tons of carbon per year from 2015 to 2020. This accounts for roughly 30 per cent of the world's land-based carbon absorption. Climate models predict that by the 2050s, the hot and dry conditions that led to the 2023 fires could become the norm.
“Canada’s present strategy adopts a risk-based approach, for which decisions on whether or not to suppress fires are made on a fire-by-fire basis. Understanding how fire regimes will change with climate change is thus of high importance, for future decision criteria and costing,” the scientists were quoted in the study.